(not commiting any files that were reported as broken, there are many!)
Original size: 130846 KiB on 10530 files
Optimized size: 127520 KiB
Total saving: 3325 KiB = 2% decrease
Overall statistics (only for files with a smaller recompressed size):
Original size: 71209 KiB on 4533 files
Optimized size: 64830 KiB
Total saving: 6379 KiB = 8% decrease
...as the focus arrows are supposed to be the brightest.
Added/updated imagemagick_command.txt for both standard and highlighted arrows.
Ran wesnoth-optipng over all arrow images:
Overall statistics (only for files with a smaller recompressed size):
Original size: 261 KiB on 121 files
Optimized size: 241 KiB
Total saving: 19 KiB = 7% decrease
